Changeset 445 in xtideuniversalbios for trunk/Configurator/Src/Libraries/math.asm

Timestamp:

Aug 29, 2012, 12:59:23 PM (12 years ago)

Author:

krille_n_@…

google:author:

krille_n_@hotmail.com

Message:

Changes:

• A speed optimization to the eSHL_IM macro for 386 and higher. This change breaks emulation in the sense that the macro will fail when given a memory operand as the first parameter.
• Memory_SumCXbytesFromESSItoAL now returns with the zero flag set/cleared according to the result.
• Unrolled all the 8 bit READ transfer loops to do 16 bytes per iteration. Added a new macro (UNROLL_SECTORS_IN_CX_TO_OWORDS) as part of it. Size wise this is expensive but I think it should be worth the ROM space. The WRITE transfer loops were left as is since writes are rare anyway (<10% of all disk I/O IIRC).
• Minor optimizations and fixes here and there.

File:

• trunk/Configurator/Src/Libraries/math.asm (modified) (1 diff)

trunk/Configurator/Src/Libraries/math.asm

@@ -104 +104 @@
     push    bx
     mov     bx, dx              ; Copy hiword to BX
-    xor     dx, dx              ; Zero DX for multiplication
     mul     cx                  ; DX:AX = AX (loword) * CX (multiplier)
     push    dx                  ; Push possible overflow
     xchg    ax, bx              ; => AX=old hiword, BX=new loword
-    xor     dx, dx              ; Zero DX for division
     mul     cx                  ; DX:AX = AX (hiword) * CX (multiplier)
     pop     dx                  ; Pop possible overflow from first mul